I think I agree with a lot of what you said - non-CS classes can be fundamental to learning some job skills (like writing, communicating, and deep thought). However when I say that it helps me drive decision making, I mean that I am literally more confident in what I'm saying because I'm reasonably sure of the boundaries in my knowledge.
For example, I went to grad school and studied databases. On that topic, I probably know more than anyone I work with; so if I put forward a proposal that is related to DBs in any way, I can be quite sure that there are no surprising edges that will come back to bite me (i.e. no one will come along and say "well what about this?", at least from a technical perspective). That's because I know what I know, and there are things I don't know, but I also feel like I know what those are (e.g. I don't feel as comfortable with low-level programming, mostly because I actually skipped a machine organization class and never picked those skills up separately).
For example, I went to grad school and studied databases. On that topic, I probably know more than anyone I work with; so if I put forward a proposal that is related to DBs in any way, I can be quite sure that there are no surprising edges that will come back to bite me (i.e. no one will come along and say "well what about this?", at least from a technical perspective). That's because I know what I know, and there are things I don't know, but I also feel like I know what those are (e.g. I don't feel as comfortable with low-level programming, mostly because I actually skipped a machine organization class and never picked those skills up separately).